1. Field of the Invention
The present invention relates to a process and an equipment for the reactivation of spent activated carbon onto which pollutants were adsorbed.
2. Description of the Related Art
Activated carbon is widely used in the purification of contaminated water and air because of its excellent capabilities of adsorbing various inorganic or organic substances.
After being used, the activated carbon is generally reactivated. The reactivation processes allow the activated carbon to recover its adsorption capacities and thereby, the reactivated carbon is re-used in the adsorption process. However, the current reactivation methods generally demand very high costs and thus, limit adopting the activated carbon-utilizing purification process.
There are various conventional methods for the reactivation of the used carbon, for example, thermal reactivation, solvent extraction or wet oxidation, etc., depending on the nature of the pollutants adsorbed on the activated carbon.
As being the most available reactivation method, the thermal reactivation requires the reactivation furnace to be processed at high temperatures of 900xc2x0 C. to 1000xc2x0 C. similar to that used in the production of the activated carbon. Therefore, the construction and maintenance of the thermal reactor demands high costs.
The existing solvent extraction method is disadvantageous because the adsorption recovery efficiency of the reactivated carbon is low and there is a possibility that a portion of the harmful solvent used remains in the reactivated carbon.
The wet oxidation method is deficient in the degradation or desorption of the pollutants irreversibly adsorbed on the activated carbon.
Therefore, there has been a need for new methods and/or equipment permitting the reactivation of the spent activated carbon, which can highly recover the adsorption capacities of the activated carbon and which also are less costlyto use and operate.
The present invention provides a method of the reactivation of spent activated carbon onto which pollutants were adsorbed, which comprises a first step of subjecting the used activated carbon to a mixed solution including ethanol, sodium hydroxide solution and water to effectuate the desorption of the pollutants adsorbed on the activated carbon.
In addition, the present invention provides equipment for reactivating the spent activated carbon onto which the pollutants were adsorbed, which comprises (A) a mixing tank for mixing given amounts of water, ethanol and sodium hydroxide solution which are supplied from respective receptacles thereof; (B) a reactivating reactor for receiving the mixed solution from the mixing tank and subjecting the spent activated carbon filled therein to the mixed solution to effectuate the desorption of the pollutants adsorbed on the spent activated carbon, wherein the reactivation reactor is provided with means for regulating temperature of the mixed solution; and (C) a storage tank for receiving the reactivated carbon.